Composite items are typically constructed from layers of material that are laminated together. The categories of materials utilized to fabricate or ‘layup’ composite items includes, for example: fiber; fabric; tape; film; and foil. Within each of these categories, a multitude of diverse materials are utilized. For example, fibers utilized includes: glass; carbon; aramid; quartz; and the like. When these fibers are arranged as woven sheets and unidirectional ribbons, they are referred to as fabric and tape, respectively.
Fiber placement is a process used to construct or fabricate composite items. These composite items include relatively simple planar sheets or panels to relatively large complex structures. The composite items are generally built up from multiple layers or plies of composite materials that are pre-impregnated with uncured resin (“prepreg”). These plies are placed on a form by a head that is positioned by a positioning device such as a robotic arm or gantry.
Composite materials are typically supplied in rolls or spools in a variety of widths. Generally, more highly contoured composite items are fabricated from relatively narrower composite materials. Composite materials having a width of about ⅛th inch to about 1 inch are typically referred to as “tow” and often, several strands of tow are placed at once in order to lay down a wider strip or “course.” A head on a tow placement device arrays a group of prepreg tows into a continuous band and compacts them against the surface of the form or layup tool. At the end of each course, all of the tows are generally cut and then rethreaded to start the next course. In addition, individual tows are sometimes cut during placement of a course to reduce the overall width, or shape, of the course. A disadvantage of conventional cutter modules in tow placement devices is that the cutters often fail. Cutter failures typically stop production until corrective measures are taken. These stoppages decrease laydown rates and increase product costs.
Another disadvantage of conventional cutter modules is that resin from the prepreg tows may foul the blades and other components of the cutter module. This fouling contributes to cutter failures and typically requires cleaning procedures to be performed. These cleaning procedures generally require the tow placement device to be shut down and may require partial disassembly. Such procedures also decrease laydown rates and increase product costs.
Accordingly, it is desirable to provide an apparatus and system capable of overcoming the disadvantages described herein at least to some extent.